In general, silver tarnish is the result of silver reacting with sulfur compounds in the air. Over time, a layer of silver sulfide will accumulate on the surface of silver material. For household utensils and silverware, the accumulation of such sulfur on the silver will diminish the value and appearance of the silverware. Often, a great deal of time is devoted to the cleaning of such silver utensils.
In the past, certain chemicals have been available for the removal of tarnish from silver. Some of these chemicals are very corrosive materials. These corrosive materials will remove a layer of silver, along with the tarnish, from the silverware. Also, the use of such corrosive materials can cause pitting in the silver surface of the utensils and silverware. Many of these corrosive materials are carcinogens and cannot be properly disposed of or used in a conventional manner.
Buffing cloths are also available for the removal of tarnish from silver. Typical buffing cloths utilize thiourea for the removal of the tarnish from the silverware. Typically, the buffing cloth is rubbed over the surface of the silverware for the purpose of removing the tarnish. Once again, this buffing technique is an abrasive process for the removal of the tarnish. A film of thiourea will remain on the silverware after the buffing.
Typically, tarnished silverware will exhibit two types of appearance. First, the tarnished pieces exhibit a copper or light brown coloring. This results from the sulfur reacting with the silver so as to form silver sulfide. This reaction depends upon the amount of sulfur in the air. For example, highly industrialized areas will have higher concentrations of sulfur in the air than other areas. The second type of appearance is a black color formed on the silverware. This black appearance results from the accumulation of waste of sulfur-eating bacteria. The bacteria are transported by the air to the surface or crevices of the silver pieces. The bacteria begins to consume the sulfur formed on the silverware. The waste product of the bacteria is a black residue on the silverware.
Heretofore, silver has not been employed for the purpose of removing sulfur from fluids or the sulfur from silver ore. A main motivating reason for the failure to use silver in this process is the inability to properly clean the silver after the accumulation of sulfur. Quite clearly, in the industrial processes, the buffing of silver screens and meshes would be very time consuming and not economically practical. The use of abrasive or corrosive chemicals for the removal of sulfur is also considered an unattractive alternative. Since these abrasive or corrosive materials are potentially carcinogenic, most industrial facilities would have serious problems in the disposal of such cleaning materials. Conventionally, industrial processes will add chemicals to the sulfur-containing fluids for the purpose of chemical removal of sulfur. Unfortunately, in the example of natural gas, the "cleansing" chemicals will remain in the natural gas stream. As a result, these chemicals can produce undesirable emissions when the natural gas is burned. If the sulfur is not removed from the hydrocarbon-containing fluid, then a noxious smell will be emitted when the fluid is burned. Additionally, dangerous sulfur oxides will be emitted during the burning of the fuel.
It is an object of the present invention to provide a composition that effectively removes sulfur from silver.
It is another object of the present invention to provide a process for the removal of sulfur from hydrocarbon and aqueous fluids.
It is a further object of the present invention to provide a process for the removal of sulfur from silver ore.
It is still another object of the present invention to provide a composition for the removal of sulfur from silver that is environmentally safe, biodegradable, and non-hazardous.
It is still another object of the present invention to provide a composition that requires no buffing and will not harm silver.
It is another object of the present invention to provide a composition that quickly and inexpensively removes sulfur from silver.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.